Filters having replaceable filter cartridges are well known in the art. An exemplary filter having a tank or vessel with replaceable filter cartridges is disclosed in Soriente et al., U.S. Pat. No. 3,279,608. Such filters are used in numerous industries to filter liquid streams of particulate and dissolved matter. Generally, the filter vessels have an inlet nozzle and an outlet nozzle. A typical vessel includes a tube sheet which spans across at least a portion of the vessel and defines an influent chamber in communication with the inlet nozzle and a filtrate chamber in communication with the outlet nozzle.
In a typical arrangement, cores or sepia extend from the tube sheet into the influent chamber. When used with filter cartridges, a cartridge is positioned on and mounted to the core. A detailed description of the operation of such a filter vessel is disclosed in the aforementioned patent to Soriente et al., which patent is incorporated herein by reference.
Filter vessel configurations are generally of two types, upflow and downflow-type vessels. In a downflow-type vessel, the septa extend upwardly from the tube sheet and the flow is into the vessel from an upper nozzle, downward through the filter elements and out of the vessel through a lower nozzle. Conversely, in an upflow-type vessel, the septa extend downwardly or depend from an upper tube sheet or bulkhead. The flow is into the vessel through a lower nozzle, upward through the filter elements and out of the vessel though an upper nozzle.
In order to remove or install the filter cartridges, it is necessary for personnel to reach into the vessel to remove a mounting assembly which holds the cartridge in place. Some known assemblies consist of many small parts which must be carefully handled to prevent dropping parts into the filter vessel while removing the mount. Other known assemblies require performing some task near the base of the cartridge to remove the cartridge from the core and the vessel.
In most instances, these tasks are not hazardous. However, when the filter is used in toxic or radioactive systems, not only may the environment be hazardous, but the time permissibly spent in the location and in the vessel may be severely limited. Numerous devices have been developed in order to facilitate remote removal of the filter mount and associated filter. These devices, however, often require the use of highly specialized tools which are not readily available. An example of such a device is disclosed in U.S. Pat. No. 3,664,003 to Wapner et al. This device works well in certain applications, however, it requires the use of a lift plate which remains in the tank during operation.
Other apparatus which facilitate filter cartridge removal are disclosed in U.S. Pat. Nos. 4,174,282 to Butterworth and 4,210,537 to Butterworth et al. These apparatus also operate quite well and permit quick filter element removal. However, the mounting assembly is located at or near the tube sheet which may, in certain instances, make filter cartridge removal and replacement and mount assembly maintenance a difficult and time consuming task.
Another mounting assembly is disclosed in U.S. Pat. No. 2,914,179, to Foust. The device disclosed in Foust includes a spring which is set into a filter element mount, between a plate and a fixed collar.. Thus, the assembly of Foust does not appear to provide the capability to adjustably pre-load the filter element with a predetermined compressive load to assure that the filter will remain in place during operation.
Thus, there continues to be a need for liquid filter having a quick-disconnect filter element mounting assembly which assembly is readily accessible from an opening in the vessel at a distance from the tube sheet, which utilizes a minimum number of parts and which facilitates rapid, tool-less removal and replacement of filter elements.